1. Field of the Invention
The present invention relates to a semiconductor element which is used for a light emitting diode or the like which is suitable for a light source of a display, illumination, an optical communication or an office automation equipment or the like and more particularly to a semiconductor element which is excellent in brightness and mass productivity.
2. Description of the Related Art
In an electrode (a p-side electrode) of a conventional semiconductor element (a nitride semiconductor element 100), a translucent electrode layer (a translucent electrode 60) is provided on a p-type nitride semiconductor layer 40 for evenly diffusing current and improving the output of the semiconductor element 100 as shown in FIG. 12. Further, a pad electrode (a p-side pad electrode 70p) formed of metallic materials by sputtering, vapor deposition or plating is provided on the translucent electrode 60 for wire bonding. A semiconductor element has been also disclosed in which a structure of an electrode is changed from a conventional structure (see Unexamined Japanese Patent Application Publication No. 2009-94108, for example). With such an electrode, a structure has been tried to be developed which prevents the electrode from being peeled off when a wire is bonded and a structure has also been tried to be developed which prevents the electrode from being peeled off during the operation of the semiconductor element (see Unexamined Japanese Patent Application Publication No. 2010-40654, for example).
However, there has been the following problem in the conventional technique. Namely, there is still a need to improve the effect of preventing the peeling of the electrode although the structure which prevents the peeling of the electrode when a wire is bonded and the structure which prevents the peeling of the electrode during the operation of the semiconductor element have been tried to be developed as described above.
As for the peeling of the translucent electrode, it has been known that if the film thickness of the translucent electrode is made thinner in the semiconductor element, the translucent electrode is difficult to be peeled off from the interface between the semiconductor layer and the translucent electrode. However, if the translucent electrode is simply made thinner, the sheet resistance of the translucent electrode becomes higher, and thus current cannot be diffused evenly in the semiconductor element 100. In other words, as the diffusion of current becomes inadequate, it causes problems that light from the semiconductor element (a light emitting element) becomes spotted, the output of the semiconductor element is decreased and the driving voltage thereof needs to be higher.